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| author | Eric W. Biederman <ebiederm@xmission.com> | 2012-08-01 19:33:47 +0200 |
|---|---|---|
| committer | Eric W. Biederman <ebiederm@xmission.com> | 2012-11-19 14:59:10 +0100 |
| commit | 0a01f2cc390e10633a54f72c608cc3fe19a50c3d (patch) | |
| tree | e713a1c45b5ce125a5d33b61d528cd45264d47a7 /fs/proc/base.c | |
| parent | pidns: Use task_active_pid_ns where appropriate (diff) | |
| download | linux-0a01f2cc390e10633a54f72c608cc3fe19a50c3d.tar.xz linux-0a01f2cc390e10633a54f72c608cc3fe19a50c3d.zip | |
pidns: Make the pidns proc mount/umount logic obvious.
Track the number of pids in the proc hash table. When the number of
pids goes to 0 schedule work to unmount the kernel mount of proc.
Move the mount of proc into alloc_pid when we allocate the pid for
init.
Remove the surprising calls of pid_ns_release proc in fork and
proc_flush_task. Those code paths really shouldn't know about proc
namespace implementation details and people have demonstrated several
times that finding and understanding those code paths is difficult and
non-obvious.
Because of the call path detach pid is alwasy called with the
rtnl_lock held free_pid is not allowed to sleep, so the work to
unmounting proc is moved to a work queue. This has the side benefit
of not blocking the entire world waiting for the unnecessary
rcu_barrier in deactivate_locked_super.
In the process of making the code clear and obvious this fixes a bug
reported by Gao feng <gaofeng@cn.fujitsu.com> where we would leak a
mount of proc during clone(CLONE_NEWPID|CLONE_NEWNET) if copy_pid_ns
succeeded and copy_net_ns failed.
Acked-by: "Serge E. Hallyn" <serge@hallyn.com>
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
Diffstat (limited to 'fs/proc/base.c')
| -rw-r--r-- | fs/proc/base.c | 4 |
1 files changed, 0 insertions, 4 deletions
diff --git a/fs/proc/base.c b/fs/proc/base.c index 6177fc238fdb..7621dc51cff8 100644 --- a/fs/proc/base.c +++ b/fs/proc/base.c @@ -2590,10 +2590,6 @@ void proc_flush_task(struct task_struct *task) proc_flush_task_mnt(upid->ns->proc_mnt, upid->nr, tgid->numbers[i].nr); } - - upid = &pid->numbers[pid->level]; - if (upid->nr == 1) - pid_ns_release_proc(upid->ns); } static struct dentry *proc_pid_instantiate(struct inode *dir, |